Material Substitution 9310 steel 4

[mewhg]

We have legacy part traditionally made from 9310 AQ steel, vacuum carburized and shotpeened. It is highly loaded in a semi-shock mode and under low cycle fatigue (75k cycle expected lifespan). Failure (cracking) of the component has always been a problem way before 75 k is reached. Changing geometry of the part is not an option.

Can anyone suggest a different steel that might be a better candidate for the high load/low cycle fatigue situation? I am thinking that 9310 is more suited for lower loading and high cycle fatigue applications.

TIA

 

[TVP]

metman,

In the aged condition with a UTS ~ 300 ksi, the hardness is ~ 50-55 HRC. A little too low for optimal resistance to contact stress in gear applications, but splines would not be so severe. These alloys can be nitrided, so perhaps that would be an option.